Nanotechnology goes out on a wing

What does a colorful and noisy backyard insect have to do with nanotechnology? Plenty, according to Jin Zhang and Zhongfan Liu, both professors at Peking University.

A team of researchers led by Zhang and Liu have used the wings of cicadas, ubiquitous insects best known for their acoustic skills, as stamps to pattern polymer films with nanometer-sized structures. The wings of these insects are characterized by highly ordered arrays of closely spaced microscopic pillars. When these wings are pushed down upon a smooth polymer film, they create a negative imprint of the array pattern.

Zhang, Liu, and their co-workers from Peking University and Nanotechnology Industrialization Base of China have found that the insect wings possess sufficient rigidity and chemical stability and have a low enough surface tension to be used as stamps to pattern polymer films on silicon substrates. A low surface tension is necessary so that the wings do not stick to the substrate and can be released without destroying the imprinted structures.

Quite remarkably, the wings have a waxy coating, which imparts an intrinsically low surface tension to these structures, making them ideal for use as stamps. An ordered array of microscopic wells can be obtained on the polymer film by using the pillar array on the wings. This pattern can be transferred to silicon by an etching process, leading to the formation of 'nano-wells' on a silicon chip.

Silicon wafers patterned with 'nano-wells' show promising anti-reflective properties. Arrays of microscopic gold pillars can also be obtained by using the imprinted molds. These pillar arrays are almost exact replicas of the structures found on the insect wings and may be useful for optical imaging or the detection of molecules by Raman spectroscopy.

"This technique is a powerful demonstration of how natural nanostructures existing in the environment can be used to pattern microscopic structures not easily accessible by conventional microfabrication technology", said Zhang. "There is a lot that nature can teach us about nanotechnology", added Liu, citing examples of butterfly wings and lotus leaves, which are characterized by exquisitely ordered arrays of microscale and nanoscale structures.

Citation: Jin Zhang, Zhongfan Liu, et al., Cicada Wings: A Stamp from Nature for Nanoimprint Lithography, Small 2006, 2, No. 12, 1440–1443, doi: 10.1002/small.200600255

Source: John Wiley & Sons

Related stories:

Birds, bats and insects hold secrets for aerospace engineers
Natural flyers like birds, bats and insects outperform man-made aircraft in aerobatics and efficiency. University of Michigan engineers are studying these animals as a step toward designing flapping-wing planes with wingspans smaller than a deck of playing cards.
Butterfly wings may help scientists better understand photonic crystals
As technology moves forward, many scientists are looking to nature to find inspiration for the development of advanced materials that can have a variety of practical applications.
Nanojewels made easy
Butterfly wings, peacock feathers, opals and pearls are some of nature's jewels that use nanostructures to dazzle us with color. It's accomplished through the way light reaches our eyes after passing through the submicroscopic mazes within these materials.
A new species of predatory bagworm from Panama's tropical forest
University of Panama and Smithsonian researchers report the discovery of a new Bagworm Moth species, in the Annals of the Entomology Society of America. Unlike nearly all other Bagworms, Perisceptis carnivora have predatory larvae. Strangest of all, according to Annette Aiello, staff scientist at the Smithsonian Tropical Research Institute, the adult moths wrap their eggs individually in beautiful cases fashioned from golden abdominal hairs called setae, a behavior unique among insects.
A plane with wings of glass?
Imagine a plane that has wings made out of glass. Thanks to a major breakthrough in understanding the nature of glass by scientists at the University of Bristol, this has just become a possibility.
Researchers create gold aluminum, black platinum, blue silver
Using a tabletop laser, a University of Rochester optical scientist has turned pure aluminum, gold. And blue. And gray. And many other colors. And it works for every metal tested, including platinum, titanium, tungsten, silver, and gold.
New technology sharpens X-ray vision
Researchers at the Paul Scherrer Institute (PSI) and the EPFL in Switzerland have developed a novel method for producing dark-field x-ray images at wavelengths used in typical medical and industrial imaging equipment.
New x-ray technique targets terrorists and tumours
Scientists at The University of Manchester have developed a new x-ray technique that could be used to detect hidden explosives, drugs and human cancers more effectively.

News discussion:

Nanotechnology news